The objective of this activity is to develop an end-to-end data dissemination simulation tool to help in the detailed characterisation of the mechanisms for the control and mission data dissemination within a Galileo architecture incorporating inter-satellite links.

The incorporation of inter-satellite-links to the Galileo architecture is under detailed assessment by the GNSS Evolution Program, given its visible potential to:- Enhance the overall constellation command-ability- Enhance the overall constellation monitoring-ability- Simplify the Ground Segment, reducing the number of remote ground stations- Enhance the navigation message accuracy- Enhance constellation autonomyThe incorporation of inter-satellite-links to Galileo imply an important evolution of its functional and physical architecture. It enables an alternative and/or complementary mechanism for the control and mission data dissemination within the System; which detailed and complete characterization requires of sophisticated end-to-end simulation tools. The activity high level tasks are as follows:- Consolidation of the tool specification; namely functional, performance and external interfaces requirements (initial specification prepared by ESA). - Definition of the tool physical architecture; namely main physical blocks, related internal interfaces, and core algorithms.- Definition of the tool physical detailed design; namely software modules, detailed algorithms, detailed internal and external interfaces.- Development and verification of the tool.- Consolidation of the definition of the operational scenarios to be analysed (initial definition prepared by ESA).- Extensive analysis of the control and mission data dissemination (e.g. in terms of throughput, latency, PER, BER, etc.), under the above operational scenarios; which shall include at least: i) Nominal G2G FOC operational scenarios. ii) Nominal G2G IOC to G2G FOC operational scenarios iii) Preventive and corrective maintenance (at ground or/and space segment) iv) Contingencies (at ground or/and space segment)The final result of the activity shall be a tool to assist in the design of INter Satellite links for the Next Generation of GNSS.